Air conditioning apparatus



p 12, 1939- M. L. MUELLER 2,172,399

AIR CONDITIONING APPARATUS Filed Sept. 9, 1935 2 Sheets-Sheet l i M .\v

MoRtTz L. MUELLER,

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Sept? 9 9- M. L. MUELLER AIR CONDITIONING APPARATUS Filed Sept. 9, 1935 2 Sheets-Sheet 2 FIG. 6. 3m

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MORITZ LMUEL Patented Sept. 12, 1939 UNITED STATES PATENT OFFICE 15 Claims.

The primary object of the present invention is to provide an improved combination and correlation of heating, radiating and air circulating instrumentalities through the medium of which the maximum of efllciency and economy may be had. One embodiment of means for accomplishing this result is illustrated in the accompanying drawings, wherein:

Figure 1 is a view partly in elevation and partly in vertical section 01' a furnace constructed in accordance with the invention;

.Fig. 2 is'a horizontal section on line 2-2 of Fi ure 1;

Fig. 3 is a fragmentary section on line 3--3 of i ure 1;-

Fig. 4 is a fragmentary end view of the casing illustrating the indicator of the damper, hereinafter described, and

Figs. 5 and 6 are detail side and sectional views of the cartridge type filter, hereinafter described.

Like numerals designate corresponding parts in all the figures of the drawings.

Referring to the drawings, 5 designates the outer shell or casing of the furnace. A horizontal combustion chamber 8 having its walls lined with refractory material, such as a fire brick or the likaindicated at to, extends across the lower portion of the furnace, and serves in conjunction with a suitable burner to constitute the heat producing element of the furnace. For purposes of explanation, I have indicated an oil burner l of a conventional type adapted to deliver atomized oil into the combustion chamber However, i

wish it to be understood that any type of liquid or gaseous fuel burner may be employed and it is within the purview of the invention to utilize coal or any other source of fuel as the heat producing media. It is well recognized that there is a large waste of fuel in connection with many of the burners at present in use, this waste being espe cially pronounced in those cases where the gases may follow their natural tendency to rise and to reach the flue through a relatively short and unobstructed path. Under those conditions a great deal of the fuel never reaches the flash point but goes off to the flue or chimney in the form of smoke or unburned carbon.

One of my reasons for disposing the combustion chamber horizontally and lining it with refractory material is to insure that every particle of the fuel delivered into the combustion charm ber will be subjected to such intense heat through such an extended period of time as to be brought to-the flash point and to add its own energy to the flow of hot gases. To this end I preferably provide a bridge wall 8 at the inner end of the combustion chamber beneath which gases must pass on their way to the chimney. When the refractory material has become highly heated, the atomized oil discharged .thereinto is subjected throughout all its parts to such lens-like penetration of heat reflected from these refractory walls as to bring every particle of the fuel to the flash point. The horizontal disposition of the combustion chamber and the retarding influence of the bridge wall or baille 8 prevents the too swift flow of the fuel through the combustion chamber and tends to retain the atomized fuel in the combustion chamber through such an appreciable length of time as to effectively bring about complete combustion of the some. In addition, I may provide spiral ribs 5b, cast with the refractory material, and serving to set up a whirling motion of these gases and increase the length of their travel in'the hot combustion chamber. Thehighly heated gases pass from the rear portion Qof the combustion chamber upwardly and through connecting pipe iii to the space between the inner radiator shell ii and an outer radiator shell ii. The space between these shells is occupied by a two part spiral web i3. This web is in effect one web insofar as its capacity to direct the gases in a spiral "path between said shells is concerned. However, it comprises two complementary webs, one of which its is welded throughout its length to the outer shell ii and the other of which is welded throughout its length to the inner shell ii. The confronting edges of these webs are slightly separated from each other, as at M, to leave a narrow slot extending lengthwise of these webs or bafiies. These spiral webs direct the hot gases in a spiral path to the outlet flue is, which leads to the chimney.

The making of the'spiral webs in two parts, as described, has several very important func-' tional advantages in that since these webs are welded to the inner and outer shells, respectively, they constitute, in eifect, integral parts of said shells and function as highly efidcient heat tran fer media. Further, the separation of the two parts of the spiral web permits the necessary expansion and contraction of the inner and outer shells without any tendency for the welded joints to be torn loose. in addition, the provision of the open slot through the spiral web permits a limited amount of the gases to find their way directly upward without passing around the spiral path. This tends to prevent the settling of dust or soot in the passageways by keeping'the dust and soot so stirred up that it may be caught and carried along by the spiral travellinggases,

- to the chimney. Further, this slot tends to prevent the creation of objectionable back pressures upon the burner, if, by reason of abnormal activity of the burner or abnormal cholging of the outlet passages, such back pressure should tend to come into existence. It is apparent that under those circumstances the slot I would provide what would be in effect a bypass for the gases,

7 permitting them to pass to the chimney without having to travel through the normal spiral pathidly away from the inner surface of said innershell. The space between the inner and outer shells is closed at the top and bottom of said shells, as indicated at i 8. These shells are disposed within the casing 5 and the space within said casing, around said shells, is further divided by the horizontal wall I9.

The air entering the furnace and which may be return air from the space being heated, enters the casing at 20 and after passing through a suitable filter 2I enters the casing of a fan 22. This fan is of the type taking its air through end openings 23 and discharging the air laterally through an opening in the side of the fan casing. It will be observed that the center of the fan is set to one side of the center of the shells II and I2 and thus the air flow is not split by said shells but upon the contrary engages the outer shell tangentially and travels spirally around the outer shell. When the air reaches the lower edge of the outer shell, it passes beneath said shells and upwardly throughthe inner shell. This air rapidly carries off the heat from the outer and the inner shells and from the radial webs l6, the

heated air finally finding its way into the air plenum chamber 24 and thence to the several supply pipes or ducts 25, which lead to the rooms to be heated. I

The filters 2| are renewable. That is to say, these filters consist of plate-like bodies 2la of filtering material, preferably provided with marginal stiffening frames 2lb adapted to be easily and quickly slipped into place by merely opening a door 26. It has been found by experience that when thesefilters become clogged with dust and dirt and the fan can no longer supply its normal quantity of air to the surface of the radiating drums, said drums tend to overheat and the emciency of the furnace is materially reduced. It has also been found that the average householder is inclined to be very negligent with respect to the renewal of these filter units. To aid in meeting this situation, I have provided an automatically operating damper 2| disposed about in the line of and to one side of the filtering units. This damper is mounted oif center upon a shaft 28 and carries a tube 29 having a ball or other weight 30 disposed therein. The damper is so balanced by reason of the offset position of the shaft 28 and by theaction of the weight 30 that said damper is normally closed and all of the incoming air must pass through the filters. ever, if the filters become so clogged that an adequate supply of air can no longer pass therethrough, the suction upon the damper will cause the same to tip and when once tipped, the ball HOW- or weight 30 will roll to the opposite end of the tube and maintain the damper in fully open position. Any suitable means may be employed for indicating to the householder that the damper has operated and that the filtering material should be promptly renewed. The signal may be visual or audible. It may consist of a simple pointer or semaphore upon the shaft of the damper, as indicated at 3!, or it may consist of a bell 33 or light 33a included in an electric circuit 34, closed when the damper is moved.

It is frequently desirable to humidify the air delivered to the pipes 25 and to this end I may provide a bypass 35 leading from the air plenum chamber 24 where the air is under a condition of pressure to the suction side of the fan, as indicated at 26, and dispose therein a web of screen wire 31 upon which a fine water spray 38 discharges. This bypass may be controlled by -a damper 39 either manually controlled in a manner common to dampers or controlled by conventional humidity regulators, such as are commonly employed in this art and in the dry kiln art.

I ain aware of the fact that it has heretofore been proposed to conduct the products of combustion from a combustion chamber through a spiral path and between inner and outer shells to a chimney. Such an arrangement is suggested, for example, in the patent to Mellott, No. 679,684. However, the arrangement disclosed in my present application possesses features which render it much more efficient and economical than any other with which I am familiar.

Furnaces burnout through the failure of some spot to get aproper circulation of air thereover. Furnaces show low efliciency when the air heat removal is not even over the whole furnace surface, thus causing large sections of the furnace surface to be. ineffective heat exchangers. Many attempts have been made to cause large volumes of air to fiow evenly over furnaces with gravity air flow and where forced air circulation is used various bailies, deflectors and similar devices'have been used to throw air'currents over all furnace surfaces.

. through the inner shell.

In the furnace of the present invention positive air currents are discharged, first downwardly over the outer radiator shell and then upwardly through the inner radiatorshell. This air fiow is preferably'a whirling one induced by the fan blowing the air tangentially against the cylindrical outer surface of the outer shell. Thus, the air flows spirally over every square inch of the surface of the outer shell without the use of bailies or deflectors. This efliciency is achieved and overheating of the furnace or of the air is prevented. Further, it is to be observed that the air is passed over the furnace not only spirally but twice, thus materially increasing the length of time of contact between the air and the radiation surface. While I prefer to thus discharge the air tangentially against the outer shell and. at the upper portion of a closed air space, the only .exit from which is the path upwardly through the inner shell, it is apparent that desirable results might be achieved by discharging the air from the fan in any manner into the upper portion of this space because there is no way in which the air so discharged can get out of said space except by flowing around beneath the lower edges of the two shells and upwardly Since the space between the inner and outer shells is closed at top and bottom, the only entry into this space is through the pipe! and the only exit is through pipe IE, to the chimney. I desire to particularly emphasize the fact that the incoming air is forcibly discharged into the upper portion of the space surrounding the outer shell and thus its flow downwardly around the lower edges of the shells is not only countercurrent to the flow of gases or combustion but no dead and heated air is permitted to accumulate in the upper portion of the space which surrounds the outer shell 12. In this respect my invention differs radically from most of the furnaces with which I am familiar. Usually these furnaces have re lied upon natural draft which means that the incoming air has been introduced at a low point in the furnace and any air which finds its way into the dead air spaces above said point of intake become dead air and highly heated and thus some portions of these furnaces would fail to receive the constant cooling'which can be efiected by maintaining air circulation thereover. Where pockets of dead and heated air accumulate, burning out of the furnace parts frequently results.

It is further to be noted that the relation between my combustion chamber and the remainder of the structure is such that the hot gases of com bustion cannot rise vertically and directly through said shells as in most of the structures of this nature which have heretofore been proposed, but are caused to travel through a very long path on their way to the chimney. The time consumed travelling through this long path is so great that there is ample opportunity for the air that is heated to effect adequate and highly eficient heat exchange.

While it is common practice to filter and even to wash the air delivered. to the heating systems of buildings, 3 wish emphasize the importance of the provision oi filters so easily and quickly renewed and so controllee that the householder will be encouraged to regularly renew them. A house having air conditioning equipment provided with means for filtering the air that is being circulated, will seldom require the cleaning or" draperies or the repainting of its walls and decorations.

A further feature of advantage in the assembly herein shown and described resides in the manner in which the burner l is located beneath the fan so that the whole may he enclosed in '2. rec-- tangular casing, adopted to provide the neat and modernist-is designs so desirable under present day conditions where the furnace room is fresuently a recreation room and kept in a neat, orderly and attractively furnished manner.

The spirally disposed ribs or rifling Eb formed upon the refractory material of the furnace wall causes the hot gases of combustion to whirl in the combustion chamber and this whirling motion of the gases will be continued during their travel up the spiral passageway leading to smoke pipe IS. The continuation of the whirlihg movement of the gases is facilitated by the uneven skin friction of the walls of the spiral chamber due to the difference in diameters of the inner and outer shells. in other words, the gases must travel a higher speed along the inner surface of the outer shell than along the outer surface of the inner shell and this tends to keep up the whirling or rolling action of the gases and further increase their length of travel in the radiator.

While the particular arrangement shown and inthcradiator receiving col flue, air forcing fan described is well adapted to achieve the objects and ends described, it is to be understood'that the principles of my invention may be embodied in many widely varying forms and that the invention includes within its purview whatever changes fairly come within either the terms or the spirit of the appended claims.

Having described my invention, what I claim is:

l. A furnace assembly comprising an outer casing, a combustion chamber and burner therein, a radiator comprising an inner and an outer shell disposed within said casing, means for conducting products of combustion into the lower portion of the space between said shells, said space being closed at the top and bottom, guiding means spirally disposed between said shells and afilxed to said shells, means forming ,a chamber within the casing within which said shells are disposed, said chamber being closed at the top, and means for forcibly discharging air into. the upper portion of said chamber, and tangentially with respect to the outermost shell, the air after passing over said outermost shell passing upwardly through the innermost shell.

2. A radiating unit for hot air furnaces comprising an inner and an outer shell, means for closing the space between said shells at the opposite ends thereof, means for conducting gases into the space between said shells at one end of said shells and for conducting the gases from said space at a point adiacent the other end of said shells, and a spiral two part web having the confronting inner edges of said -parts in substantial alineznent with and slightly spaced from each other and having their outer edges secured to the respective shells, and inwardly projecting radiating members carried by the innermost shell.

3. A furnace of the character described comprising an outer casing suitable partition walls dividing said casing into a fan compartment, 2. burner compartment beneath the fan compartment, a radiator receiving chamber and a combustion chamberconip rt 1 r nent comprisnieans for closing the space between said shells at the top and ing inner and outer shells and bottom thereof, means conducting products of combustion from the coinietstion chamber compartment to and into the lower portion of the space between said shells, outlet flue adapted for connection to a chimney leading from the upper portion of the space between said shells, guiding means disposed between said shells for causing the products of combustion to travel in a tortuous path and over substantially all portions of the said shells on their way to the the fan compartment, means -for conducting return air to said air compartment and means for discharging air from said fan laterally through the side wall of the radiator receiving chamber and against the outermost; of said shells adjacent the upper end thereof, the path of the air being thence downwardly around the outermost shell and then upwardly through the innermost shell, said casing also including walls forming a compartment above said shells constituting an air plenum.

e. A structure as recited in claim 3 wherein the air from the fan is discharged both laterally and tangentially against the upper portion of the outermost of said shells.

5. A structure as recited claim 3, in combination with walls forming bypass leading ill from the air plenum to the fan casing, and air conditioning means in said by-pass.

6. A furnace assembly comprising an outer casing, a radiator therein comprisingan inner and an outer shell, said inner shell being open at top and bottom and the space between said shells being closed at the top and bottom, means for generating and delivering products of combustion into the bottom of the space between said shells at one point in the circumerential area of said space, a spiral guiding means disposed between said shell and extending from the bottom substantially to the top thereof, means for conducting the products of combustion from the space between the shells at a point adjacent the top of said shells, a. wall closing the top of the space between the outermost shell and said casing, a blower discharging air into said casing at a point adjacent the top thereof and tangentially against the outermost shell to thereby cause the air to flow countercurrent to the direction of fiow of the products of combustiomsaid air after passing around the outer shell passing upwardly combustion chamber into the bottom of the space between said shells at one point, guiding means for the products of combustionbetween said shells which conduct the delivered products of come bustion under natural flow and in a tortuous path upwardly between said shells, a discharge outlet leading from the upper portion of the space between said shells to a flue, air forcing means delivering air forcibly and laterally into the top of the space between the main casing and the outermost of 'said shells, means closing the top of the last named space, the lower portion of the radiator comprised by said shells being spaced from the top of the combustion chamber a suflicient distance to permit the air to flow downwardly around the outermost shell, around the lower edges of said shells and upwardly through the innermost shell, and an air plenum above said shells.

8. A structure as recited in claim 7, in combination with a by-passbetween the air plenum and'the air forcing means, and air conditioning means in said by-pass whereby airvmay be con tinually drawn from the air plenum, conditioned,

and returned to the current of air being forced over the said shells.

9. A structure as recited in claim 7 wherein the discharge of air from the air forcing means is directed tangentially of the outermost of said shells to initiate a spiral flow of the air around said shells.

10. In an apparatus of the character described for supplying conditioned air to a given space, a heating plant having a hot air chamber, a return air conduit leading from said space to the heating plant, .warm air discharge conducts lead ing from the hot air chamber of the heating plant to said space, a humidifying unit, a by-pass conduit connecting said humidifying unit with said hot air chamber and said return air conduit for conducting air from the hot air chamber through the humidifying unit and to said return air conduit, and means for drawing air through said bypass conduit and said return air conduit and passing same-to said heating plant.

11. In an apparatus of the character described for supplying conditioned air to a given space, a heating plant having a hot air chamber, a return air conduit leading from said space to the heating plant, warm air discharge conduits leading from the hot air chamber of the heating plant to said space, a humidifying unit, a bypass conduit connecting said humidifying unit with said hot air chamber and said return air conduit for conducting air from the hot air chamber through the humidifying unit and to said return air conduit, means for drawing air through said by-pass conduit andsaid return air conduit and passing same to said heating plant, and means for controlling the amount of air'passing through said by-pass conduit.

12. A device ofthe character described comprising a main casing, a radiator within the main casing comprising a pair of spaced shells, the

space between which is closed at its ends by end walls,'a combustion chamber, means for delivering the products of combustion from the combustion chamber into the space between said shells at a point adjacent one end of said shells,

w guiding means for the products of combustion,

disposed between saidshells, which conduct the delivered products of combustion in a tortuous path toward the other end of said shells, a discharge outlet leading from the said space be. tween the shells adjacent the said other end thereof to' a point of discharge, air forcing means delivering air forcibly into the main casing and tangentially against the side of the outer shell at a point adjacent one end thereof, the said air passing spirally around said outer shell and around the ends of said shells and entering the inner shell at that end of the inner shell remote from .the point of entry of the said air into the main casing, and means for conducting the heated air which passes through the inner shell from the other end of the inner shell to a point of use.

13. As a radiating unit for hot air furnaces,"

an inner and an outer shell and means for closing the space between said shells at the opposite ends thereof, and a two-part web between said shells acting as guiding means for products of combustion, one part of'said web-being afilxed to the outer shell and the other part being affixed to the inner shell, the two parts of said web being in such juxtaposition as to comple-r mentally form a guide betweensaid shells with out being actually attached to each other, said webs being disposed to complementally direct products of combustion circumferentially of said shells.

14. Aradiating unit for hot air furnaces comprising an inner-and an outer shell, means for closing the space between said shells at the opposite ends thereof, means for conducting gases 15. A radiating unit for hot air furnaces com- 76 I prising an inner and an outer shell, means for closing the space between said shells at the opposite ends thereof, means for conducting gases into the space between said shells at one end of said shells and for conducting the gases from said space at a point adjacent the other end of said shells, and a two part web having the inner portions of said two parts in juxtaposition to and spaced from each other and having their outer edges secured to the respective shells, and inwardly projecting radial webs carried by said inner shell, the two-parts of said web bcng complementally disposed to direct products of com- 5 bustion circumierentially of said shells.

MORI'IZ L. MUELLER. 

